Leonard: You may be from Texas, but I'm from New Jersey.

(Leonard & Alice are kissing)
Leonard: Damn it, I can't. I can't do this.
Alice: Is it my tongue stud? 'Cause if that freaks you out, you're in for a real surprise later on.

Leonard: Well, they say at the end of your life, you regret the stuff you didn't do more than the stuff that you did. And, I'm pretty sure Alice is the stuff I want to do.

Leonard: Oh. Watch out, Sheldon. This little boy Casper is a g-g-g-ghost!
Sheldon: Droll.
Howard: Not as droll as a grown man passed out in a puddle of his own urine.
Leonard: That was pretty droll. With a hint of ammonia.

(After Sheldon passes out after the Halloween prank)
Howard: who had there money on faint?
Raj: I had pee his pants.
Leonard: Hang on, looks like everyone's a winner.

Leonard: You see, I used to be a jackass, but I stopped myself. I became a good guy. See, that's kind of my superpower. I'm like Captain Good Guy!
(Alice pushes him out, then slams door)
Leonard: It's okay. Did the right thing. *tightens his jacket* You idiot!

Leonard: It's kinda like the Loch Ness Monster. Maybe there's something there, maybe there isn't. We'll never know but sometimes it's fun to creep yourself out thinking about it.

Leonard: Going to Wheaton's party is not betraying you.
Sheldon: Oh, of course you would have to believe that. Evil always thinks it's doing right. Excuse me, Stormtrooper. These are the droids you're looking for.
Leonard: I'm going to a party. I'm not turning R2-D2 and C-3PO over to the empire!
Sheldon: Not yet.

Stuart: You want me to wrap it?
Leonard: No, it's okay. I'm gonna stab my friend in the chest.

Leonard: Sheldon, can you grab me a water?
Sheldon: Possibly.
Leonard: Can you or can't you?
Sheldon: It's not that simple, Leonard.
Leonard: It never is, is it?

Leonard: Pretty cool about Howard, huh?
Sheldon: Dont talk to me as if nothing's happened between us. And yes, it sure is, buddy.
Leonard: For God's sake, will you stop with the Schrodinger stuff?
Sheldon: Would you prefer a simpler application of Heisenberg's uncertainty principle, in which I could either know where you are or whether I like you, but not both?
Leonard: You never stop talking, do you?

Leonard: Can we get autographed dolls?
Brent Spiner: Sure. Twenty bucks.
Leonard: Ten.
Brent Spiner: Eighteen.
Leonard: Twelve.
Brent Spiner: Sixteen.
Leonard: Two for thirty. And you come to my birthday party.
Brent Spiner: Done.

Leonard: See, this is the good thing about having a girlfriend 9,000 miles away. I can spend my nights doing whatever I want.
Howard: You mean like playing nerd games with us and then taking a suspiciously long shower?
Leonard: Maybe.

Leonard: Are you gonna eat that whole pie?
Raj: Maybe. Why not? Who do I have in my life to watch my figure for?
Leonard: Oh, God, did you watch Bridget Jones again?
Raj: No, its just that everybody's got someone. Sheldon's with Amy, Howard's getting married, you're dating my sister.
Leonard: Now that Howard's getting married, maybe he'll inflate one of his old girlfriends for you.

Penny: Mustache is looking good there, Sheldon.
Sheldon: Don't thank me. Thank the dice. They told me what percentage of my face to shave.
Howard: Why are you still doing this?
Sheldon: Because it's working. In the past few weeks, unburdened by trivial decisions, I've co-authored two papers in notable peer-reviewed journals, and I'm close to figuring out why the Large Hadron Collider has yet to isolate the Higgs boson particle.
Leonard: You left out, got chafed testicles because you no longer wear underpants.